Master of Science, The Ohio State University, 2012, Horticulture and Crop Science

Invasive plants that spread through natural areas are likely to threaten sensitive and unique habitats. Since it is impossible to kill every individual invasive plant, managers need landscape-scale strategies to direct management efforts along invasion sites and corridors of spread. Therefore, managers need information of how invasive plants spread over time and space with respect to sensitive habitats. Ligustrum vulgare L. (common privet) is a woody invasive plant that is spreading to sensitive habitats in eastern North America. To assist in developing efficient management approaches for this species, we studied the spatial genetic structure of L. vulgare across the landscape within the 325-acre Wooster Memorial Park (WMP) and in three states, using sequences from two chloroplast DNA (cpDNA) genes. For samples taken within the park, we combined patch age, spatial features, and genetic data to reconstruct invasion history and analyze spatial distribution patterns. We conducted a comprehensive survey in the park, mapping and sampling established stands of L. vulgare. Ages of 331 patches in WMP were determined by examining tree-rings. DNA was extracted from samples taken from eight sites in Ohio and two adjacent states along with 313 samples from WMP. Haplotype networks were constructed, and 10 to 17 haplotypes were identified. Haplotype frequencies were geographically different among study sites. Lower genetic diversity was found in the eight Ohio sites compared to sites in New York and Pennsylvania, suggesting an invasion pathway from east to west. In the park, invasion time and three invasion phases were revealed. A similar invasion time and invasion process was observed for all haplotypes. Initial invasion sites were located and their favorable habitats were identified. New establishment and spatial patterns were described through mapping distributions of patches over time. For spatial analyses, we used nearest neighbor analysis, global Moran's I, and local Gi* st (open full item for complete abstract)

Committee: John Cardina PhD (Advisor); Andrew Michel PhD (Committee Member); P. Charles Goebel PhD (Committee Member) Subjects: Horticulture